Self-propagating high-temperature synthesis of porous graphene by magnesiothermic reaction as high-performance electrochemical electrode material

Graphene is widely used in supercapacitors due to its large specific surface area and excellent electrical conductivity. However, a large scale efficient and sustainable production of high-quality graphene is still an urgent challenge. We report a controllable self-propagating high-temperature synthesis (SHS) process to convert CO2 with a mixed powder of magnesium and zinc into porous graphene (PG). The prepared PG contains 3-6 layers, with a plenty of uniform 2-4 nm mesopores, and has a specific surface area as high as 1458 m 2 g(-1). The obtained PG was used as an electrode material for the supercapacitor and exhibited a superior capacitance performance. At a current density of 1 A g(-1), the specific capacitance can reach 177 F g(-1). Capacitance retention rate is as high as 91% after 10,000 cycles at a current density of 5 A g(-1). In addition, the charge-discharge curve remains approximately triangular at a current density of 20 A g(-1), which shows satisfactory capacitance properties. We expect that our results will contribute to the development of the large-scale graphene synthesis technology based on a use of the SHS method aimed for the application as high-performance supercapacitor materials. (C) 2021 Elsevier B.V. All rights reserved.